Heating And Cleaning Apparatus For Surface Treatment

ABSTRACT

A heat gun for cleaning and heat treating surfaces uses a lightweight jet engine to generate a hot blast of exhaust, with aggregate injectors in an engine jacket arranged over the jet engine admixing a cleaning medium with the hot exhaust. The cleaning medium admitted into the hot exhaust jet is discharged through an exhaust nozzle 1 directed at the item to be treated. The engine is controlled electronically and advanced on a lightweight frame  5,  which may be fitted with a ballast weight  9  and spacer wheels  10,  or be mounted on an advancing arrangement  8.  The jet engine is powered by liquid fuel supplied from a tank  6.  Intake air is cleaned and sound-damped in a filter unit  3.  Combustion takes place at a high pressure and the exhaust discharged hot in a high velocity exhaust jet containing the cleaning media.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of PCT International patent application No. PCT/DK2011/000047, filed 18 May 2011, claiming priority in Danish patent application no. PA2010 00441, filed 20 May 2010, the contents of which are hereby incorporated by reference.

TECHNICAL FIELD

The invention relates to a tool for surface treatment by cleaning and drying of surfaces, joints and the like, where the intention is to remove weathering, wear or unintentionally added coatings prior to further surface treatment, if any.

BACKGROUND

Mutually independent systems are often used in the methods known today for the cleaning and heat treatment of surfaces and items. First, cleaning is performed by a high-pressure system with water or air directly or with admixture of cleaning agents, such as, by way of example, sand, and subsequently heat treatment is performed with gas burners with a naked or indirect flame. In principle, the known technique has all the requisite characteristics, but it is inexpedient to first employ heavyweight high-pressure systems powered by diesel or petrol engines, which discharge heat directly into the environment through their exhaust and cooling systems, and to then employ a second source of energy for subsequent heat treatment by gas burners supplied from pressurized gas systems, which, in addition to the drawback of handling and transporting “hazardous goods”, now also constitute a serious security problem due to the risk of terrorism, which has led to the imposition of very severe security requirements and restrictions for workplaces which use and store gas in pressurized cylinders and tanks.

It is known from patent publication GB 614725A to employ hot exhaust air generated by the exhaust of a jet engine, which, after being discharged through a pipe and hose system, is admitted to a work area where a dosing device for the admixture of sand or the like is added to an exhaust nozzle, which can thus clean by sandblasting.

SUMMARY OF THE INVENTION

The invention provides an effective tool for cleaning and heat treatment in one operation, whereby disadvantages of the known technique are remedied. This is achieved in accordance with the invention by using a lightweight turbojet engine with an engine jacket with a connecting member, which, supplied with an aggregate injector, is capable of dosing one or more aggregate materials into the exhaust jet, which thereby cleans and dries the blasted area while being advanced manually or by a self-propelling unit.

The invention uses a lightweight jet engine in which a liquid fuel, such as, by way of example, petrol or diesel oil, is injected under electronic control into a compressed combustion chamber, out of which the exhaust air is discharged from the engine jacket with an aggregate injector for sand or similar cleaning medium, which is dosed and discharged through one or more exhaust nozzles to the surface to be cleaned. The jet engine sucks in clean air through a dirt and noise reducing filter unit, which may be mounted directly on and around the engine unit, or be disposed at a distance from the cleaning area, supplying clean air through a system of hoses or the like. The exhaust nozzle may be adapted for various tasks, for example narrow and pointed for depth treatment of joints and cracks, or flat and wide for surface treatment. When the exhaust jet is directed at an item to be cleaned, the exhaust nozzle will be affected strongly by an oppositely directed impact which will attempt to lift the nozzle off the item, and therefore it may be expedient to use an adjustable ballast weight and spacer wheels to facilitate advance and to maintain a suitable distance between the nozzle and the item. A heat gun may be constructed for simple manual operation, mounted on a lightweight frame or trolley, or a number of these may be mounted together on a self-propelled, manned or remote-controlled advancing arrangement.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained more fully below with reference to the drawing, in which:

FIG. 1 shows a heat gun according to the invention for simple operation, with fuel and aggregate in a lightweight arrangement, which are admitted through hose connections not shown here.

FIG. 2 shows multiple heat guns mounted in an arrangement which may be mounted on a self-propelled, manned vehicle, or be advanced under remote control.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a heat gun with a lightweight jet engine mounted under an engine jacket 2, with an aggregate injector for admitting cleaning medium into the hot exhaust jet, which is discharged through an exhaust nozzle 1. The intake air is passed through an air and noise filter unit 3, and the jet engine is controlled here by a control device disposed in a handle 4. Everything is mounted here on a simple lightweight and mobile frame with an armrest 5, where a fuel tank 6 and an aggregate container 7 are carried along on a lightweight trolley 8. Here, the heat gun is shown fitted with an adjustable ballast weight 9 and adjustable load-relieving and spacer wheels 10.

FIG. 2 shows a second embodiment of a heat gun with multiple engine units 2, with exhaust nozzles 1 and an intake filter 3, here mounted in an advancing arrangement 8 which can carry along fuel 6 and aggregate materials 7. Here, everything is advanced and controlled from a self-propelled, manned or remote-controlled unit, not shown.

A heat gun for the cleaning and heat treatment of surfaces, joints and the like using hot blast air generated by a turbojet engine, is characterized by an engine jacket (2) with an injector for admixture of a cleaning medium which is discharged through an exhaust nozzle (1). Intake air may be supplied to the engine through an air filter unit (3). The heat gun may be set up on a lightweight frame for manual advance. Alternatively, the heat gun may include one or more engine jackets (2) mounted in an advancing arrangement (8). In one embodiment, the exhaust nozzle (1) is configured as a long narrow nozzle for the treatment of cracks and joints. In another, the exhaust nozzle (1) is configured as a short wide nozzle for the cleaning and heat treatment of surfaces. The heat gun may include an adjustable ballast weight (9), mounted to counteract lifting on application of force from the exhaust nozzle (1) and/or be fitted with adjustable load-relieving and spacer wheels (10).

In summary, a heat gun for the cleaning and heat treatment of surfaces, joints, cracks and the like uses a hot blast jet produced by the exhaust jet of a jet engine, where aggregate injectors have been added in the engine jacket for the admixture of a cleaning medium, such as sand, granulate material or liquid. The heat gun exhibits a lightweight jet engine arranged under an engine jacket 2, with an aggregate injector, which is capable of dosing a cleaning medium admitted into the hot exhaust jet, for discharge through an exhaust nozzle 1 directed at the item to be treated. The engine is controlled electronically by a device 4 and is advanced on a lightweight frame 5, which may be fitted with a ballast weight 9 and spacer wheels 10, or be mounted on an advancing arrangement 8. The jet engine is powered by liquid fuel supplied from a tank 6. Intake air is cleaned and sound-damped in a filter unit 3, and the combustion takes place at a high pressure and is discharged hot and in a high velocity exhaust jet, into which the cleaning media is fed from a tank 7. 

1. A heat gun for the cleaning and heat treatment of surfaces comprises: a turbojet engine for generating a hot blast of exhaust through an exhaust nozzle (1); and, an engine jacket (2) having an injector for admixture of a cleaning medium with the exhaust which are discharged through the exhaust nozzle (1).
 2. The heat gun according to claim 1, further comprising a lightweight frame for manual advance of the turbojet engine and engine jacket.
 3. The heat gun according to claim 1, further comprising two or more engine units (2) mounted together in an advancing arrangement (8).
 4. The heat gun according to claim 1, further comprising an air filter unit (3) for filtering intake air supplied to the turbojet engine.
 5. The heat gun according to claim 1, wherein the exhaust nozzle (1) is configured as a long narrow nozzle.
 6. The heat gun according to claim 1, wherein the exhaust nozzle (1) is configured as a short wide nozzle.
 7. The heat gun according to claim 1, further comprising an adjustable ballast weight (9), mounted to counteract a lifting force from discharge of the exhaust against the surface receiving the treatment.
 8. The heat gun according to claim 1, further comprising wheels (10) for supporting movement of the heat gun. 